<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>点击</button>
    <button>点击</button>
    <button>点击</button>
    <script>
        // 改变函数内this指向
        // bind 绑定 捆绑
        var btns = document.querySelectorAll('button');
        for (var i = 0; i < btns.length; i++) {
            btns[i].onclick = function () {
                console.log("i");
                this.disabled = true;
                setTimeout(
                    function () {
                        this.disabled = false;
                    }.bind(this),
                    2000)
            }
        }
    </script>
</body>

</html>